While I certainly hope the couple is found soon, as far as I know, the car has not yet been found. In news reports, the mother of the missing Sophia Edwards, Michelle Edwards said “Sheriffs say that they got a ping off a cell tower in Wrightwood…so we know that they made it off the mountain.”
It sounds like she may think a ping in Wrightwood means the couple were in or around Wrightwood, but actually they could have been quite far away. While she of course may know something we don't know, it seems dangerous to arrange a search and call for volunteers and rock climbers without better info about a specific area.
If a specific area in the mountains were identified, well-trained local search and rescue teams would be all over it. If a less remote area was identified, a search by volunteers might make more sense.
Maybe they just want to examine places a car might have gone off the edge of a road. That might make sense, though presumably LE has already done a lot of that. I hope that the people organizing the search understand the limitations of cell phone localization and that any searchers stay safe.
JMO